On Sep 21, 10:51*pm, Alex <metallourla...@gmail.comwrote:
Why? I'm coping data_set in ds so why data_set is changed?
You're making a copy of the ds tuple, which has the -same- contents as
the original. To create copies of the contents as well, try the
deepcopy function from the copy module.
As an aside, you're also trying to make a copy of ds for each
iteration of the loop, which is unnecessary in this case. Here's a
slightly better example of your code:
>>from copy import deepcopy
data_set = ({"param":"a"},{"param":"b"},{"param":"c"})
ds = deepcopy(data_set)
for i, data in enumerate(ds):
.... if i == 1: data['param'] = "y"
.... if i == 2: data['param'] = "x"
....
>>print data_set
({'param': 'a'}, {'param': 'b'}, {'param': 'c'})
>>print ds
({'param': 'a'}, {'param': 'y'}, {'param': 'x'})
Although your use of a tuple full of dicts for data_set is kinda
strange... Tuples are generally used when you want a structured data
element, in which case you'd just address each element directly rather
than iterate through it:
>>ds = deepcopy(data_set)
ds[1]['param'] = "y"
ds[2]['param'] = "x"
